if 5>12:
    print("5 is greater than 12")
else:
    print("5 is less than 12")


age=30
if age>=18:
    print("you are underaged")
elif age>=18 and age<=25:
    print("you are young")
elif age>=25 and age<=50:
    print("you are middle-aged")
else:
    print("you are old")


#闰年
    year = int(input("请输入年龄："))
    if (year%4==0 and year%100!=0) or (year%400==0):
        print("%d是闰年" % year)
    else:
        print("%d不是闰年" % year)



# ctrl+alt+L格式化代码


a = int(input("请输入a:"))
b = int(input("请输入b："))
c = int(input("请输入c："))
if a>b:
    if a>c:
        print("a is the largest")
    else:
        print("b is the largest")
else:
    if b>c:
        print("b is the largest")
    else:
        print("c is the largest")


#计算机实现加减乘除


num1 = float(input("请输入数字"))
num2 = float(input("请输入数字"))
op = input("请输入运算符：")
if op == "+":
    print(num1+num2)
elif op == "-":
    print(num1-num2)
elif op == "*":
    print(num1*num2)
elif op == "/":
    print(num1/num2)
else:
    print("invalid")